Most individuals buy and use a hair shampoo for its cleansing properties. Furthermore, in addition to clean hair, the consumer desires sufficiently-conditioned hair that holds a preset configuration. However, present-day hair shampoos generally are formulated with highly-effective synthetic surfactants, like anionic surfactants, that exhibit a high foam and primarily clean, as opposed to conditioning, the hair Therefore, it is not surprising that hair shampoos neither help detangle wet hair nor impart any residual hair conditioning benefits to dry hair, such as the manageability or styleability of hair sets.
Consequently, after shampooing, the hair normally is left in a cosmetically-unsatisfactory state because an anionic surfactant-based hair shampoo composition not only removes all of the dirt and soil from the hair, but also removes essentially all of the sebum that is naturally present on the surface of the hair fibers. Therefore, it was found that the properties of anionic surfactants that effectively cleanse the hair also serve to leave the hair in a cosmetically-unsatisfactory condition. In general, therefore, shampooing the hair with a hair shampoo composition including an anionic surfactant, or a nonionic surfactant or an amphoteric surfactant, leaves the hair, after rinsing with water, with an undesirable harsh, dull and dry touch or feel, usually called "creak".
As a result, thoroughly cleansed hair is extremely difficult to comb, in either the wet or dry stage, because the individual hair fibers tend to snarl, kink, and interlock with each other. In addition, incompletely dried hair, such as hair dried with a towel, has poor brushing properties. Then, after complete drying, the hair does not set well. Furthermore, the combing or brushing property of the dried hair remains poor. The dried hair also has undesirable electrostatic properties in a low humidity atmosphere that cause the hair to "fly away", thereby further reducing the brushing property of the hair. The unsatisfactory combing or brushing property of freshly-shampooed hair also causes hair damage, such as split ends or hair breakage. In addition, the natural luster and resiliency of the hair is reduced.
Accordingly, freshly-shampooed hair usually requires a post-shampoo hair treatment with a conditioning composition to improve the unsatisfactory physical and cosmetic condition of the hair. A conditioning composition normally is applied separately from the hair shampoo, and usually is a rinse or a cream-like lotion containing a cationic compound. Therefore, investigators have sought hair shampoo compositions that generate a copious and stable amount of foam, cleanse the hair and leave the hair in a cosmetically-satisfactory state, such that the subsequent treatment with a conditioner composition can be avoided.
Consequently, investigators sought a composition that behaves both as a shampoo and as a hair conditioner. However, the resulting shampoo-conditioner compositions possessed several disadvantages. For example, it is known in the art that anionic surfactants generate a high foam and are suitable for cleansing the hair, and that, in many instances, cationic compounds, like cationic surfactants and polymers, are suitable hair conditioners. However, the major difficulty encountered by investigators is the inherent incompatibility between an anionic surfactant and a cationic surfactant or cationic polymer. Consequently, contact between the anionic surfactant and the cationic surfactant or cationic polymer either produces an intractable precipitate that forms immediately, or causes an interaction between the anionic and cationic components that significantly reduces their respective foam generating, cleansing and conditioning properties. The reduction in foaming, cleansing and conditioning effectiveness also is observed in compositions wherein the anionic and cationic components do not precipitate from the composition, but remain in solution or in a suspended state.
The inherent incompatibility between an anionic compound and a cationic compound is well recognized by workers skilled in the art. For example, Sagarin in Cosmetics, Interscience Publishers, Inc., New York, p. 538, 1957, states that anionic and cationic compound cannot be used in combination because they react to form insoluble salts. Thus, in practice, consumer needs traditionally have been met by applying a high-foaming and nonsubstantive anionic surfactant-based shampoo to the hair to cleanse the hair, then rinsing the hair, followed by applying a conditioner composition including a substantive cationic compound to the hair to condition the hair.
As previously discussed, freshly-shampooed hair, being inclined to knot and tangle, is difficult to manage and comb. The wet combing problem has been solved by treating freshly-shampooed hair with a conditioner composition that includes a compound to coat the hair shaft and cause the individual hair shafts to resist tangling and matting because of conditioner compound residue on the hair shaft. Until recently the desirable properties of both a hair shampoo and a hair conditioner composition could not be incorporated into a single composition. Therefore, a shampoo composition and a conditioner composition were applied sequentially to achieve the benefits provided by each composition. Investigators attempting to combine all, or some, of the beneficial properties of a shampoo composition and of a conditioner composition into a single shampoo-conditioner composition concentrated particularly on incorporating the properties of a post-shampoo conditioning rinse into a hair shampoo composition.
Therefore, because hair shampoo compositions are predominantly anionic in character, the incorporation of a substantive cationic compound into an anionic shampoo composition ranges from difficult to impossible because of the inherent incompatibility between anionic and cationic surfactants. Nevertheless, a combination shampoo-conditioner composition is desirable because of the convenience such a combination product offers to the consumer. In such a shampoo-conditioner product, the anionic surfactant acts to rid the hair and scalp of dirt, surface film, debris, and the like, while the cationic compound deposits on the hair to provide conditioning benefits, such as manageability, shine and texture. However, until the composition and method of the present invention, it has proven difficult to provide a stable hair shampoo-conditioner composition because of the inherent incompatibility between cationic and anionic surfactants. Consequently, and in accordance with an important feature of the present invention, a polymeric cationic conditioning compound is incorporated into a composition wherein an interaction between the anionic and cationic components of the composition is essentially precluded. The hair shampoo-conditioner composition then is utilized to cleanse the hair and, simultaneously, to impart conditioning properties to the hair. In addition, the composition generates a copious and stable foam level that usually is demonstrated only by a hair shampoo composition absent a conditioning compound.
Therefore, the need for an effective and stable shampoo-conditioner composition that cleanses the hair and conditions the hair, i.e., renders the hair more manageable, in a single hair treatment has long been recognized in the art. Accordingly, although conditioning compositions for application to previously-shampooed hair are well known, only recently have shampoo-conditioner compositions become available. For example, some shampoo-conditioner compositions are specially formulated for mildness, and accordingly low detergency, in order to leave a portion of the natural oils on the hair shaft. However, hair treated with this type of composition becomes greasy, dirty looking and dirty feeling relatively quickly.
Another type of shampoo-conditioner composition includes an oily component, such as a polyglycol, a glycol ester of a fatty acid, a natural or synthetic wax or a lanolin derivative, that is deposited on the hair during shampooing. However, the oily nature of such components reduces shampoo lathering and contributes to the feeling of greasy, dirty hair relatively soon after shampooing. Another type of shampoo-conditioner composition includes a substantive cationic polymer that deposits on the hair shaft during shampooing to impart the desired degree of manageability. However, the cationic polymers utilized in the prior art also gave the hair a greasy feeling as described above. The primary difficulty encountered in preparing this type of shampoo-conditioner composition has been achieving a sufficiently stable composition without destroying the delicate balance of conditioning, cleansing, consumer appeal, foam properties, and other functional and esthetic properties. Surprisingly and unexpectedly, although the composition of the present invention includes a polymeric cationic conditioning compound, the composition is sufficiently stable, lathers sufficiently, cleanses the hair and imparts conditioning properties to the hair without a greasy feeling, while maintaining excellent physical and esthetic properties for consumer appeal.
Therefore, the present invention relates to a shampoo-conditioner composition for cleansing the hair and for imparting improved physical and cosmetic properties to the hair, such as improved combing properties, luster and manageability. It is known that anionic surfactants are especially useful for shampooing the hair and for generating a copious and stable foam level, and that cationic surfactants and cationic polymers are especially useful for conditioning the hair. In addition, combining an anionic surfactant and a cationic compound in a shampoo-conditioner composition has proven difficult because of the inherent chemical incompatibility between the two classes of surfactants. Consequently, and in accordance with the present invention, it has been found that anionic surfactants can be combined with a particular polymeric cationic conditioning compound to provide a stable and effective hair shampoo-conditioner composition. The composition is sufficiently stable to resist phase separation during storage and effectively resists an interaction between the cationic and the anionic components of the composition; but, upon application to the hair, sufficiently deposits a substantial amount of the polymeric cationic conditioning compound onto the hair to withstand rinsing from the hair during the shampooing and rinsing process.
More particularly, it has been found that a polymeric cationic conditioning compound having the formula: ##STR3## wherein n is a number in the range of from two to about 1000, and preferably from two to about 500; m is a number in the range of from one to about 18; and p and r are numbers in the range of from one to about four, when incorporated into a shampoo composition including a nonsubstantive anionic cleansing surfactant, provides a hair shampoo-conditioner composition that generates a copious and stable foam level and thoroughly cleanses the hair, in addition to depositing a sufficient amount of the cationic polymer onto the hair to condition the hair without demonstrating a greasy feeling. Such results are unexpected in the art because anionic surfactants, as a class, often are incompatible with a cationic polymer, and, if compatible, demonstrate a substantially reduced ability to generate foam. Therefore, the compatibility demonstrated by the combination of the anionic cleansing surfactant and the cationic conditioning polymer utilized in the present invention is both new and surprising, thereby permitting sufficient deposition of the substantive cationic conditioning compound onto the hair, while the anionic cleansing surfactant generates a consumer-acceptable foam level and shampoos the hair.
Overall, cationic compounds, such as cationic surfactants and cationic polymers, are known to be substantive to human hair and traditionally are used to complete the hair cleansing and hair conditioning cycle. The ability of a cationic compound to interact with the keratinous material of hair makes cationic compounds the most widely used compounds to impart the desired physical and cosmetic conditioning properties, such as wet hair detangling and dry hair manageability, to hair. Most commonly, the cationic compounds are applied to freshly shampooed and rinsed hair from a post-shampoo conditioning rinse. More recently, investigators have incorporated the cationic compound into anionic surfactant-based hair shampoos by carefully balancing the composition components to reduce or avoid an interaction between the cationic compounds and the anionic surfactants.
Cationic compounds that have been incorporated into anionic hair shampoo compositions include, for example, water-soluble proteins or protein degradation products, or polycationic polymers, such as the amino polycarbamide resins of the type described in DE-OS No. 21 50 899; polycationic cellulose derivatives of the type described in U.S. Pat. No. 3,816,616; or polycationic guar derivatives of the type described in U.S. Pat. No. 4,292,212. Many other water-soluble polymers containing cationic or quaternary ammonium groups have been proposed for use in an anionic surfactant-based hair shampoo. However, even though particular cationic compounds, especially particular cationic polymers, are compatible with anionic surfactants, a disadvantage common to all cationic hair conditioning compounds is that at least a partially-reduced conditioning effect and a substantially-reduced foam generating ability is observed when the cationic compound is included in an anionic surfactant-based hair shampoo. In contrast, and as will be demonstrated more fully hereinafter, the hair shampoo-conditioner compositions of the present invention generate a copious and stable foam, effectively cleanse the hair and impart conditioning properties to hair equivalent to properties imparted by a post-shampoo conditioner composition.
Accordingly, the present invention is directed to a hair shampoo-conditioner composition, including a nonsubstantive and high-foaming anionic cleansing surfactant and a polymeric conditioning compound, that simultaneously cleanses the hair and imparts desirable physical and cosmetic properties to the hair. By treating the hair with the shampoo-conditioner composition of the present invention, the hair is easily-combed when wet and the hair possesses satisfactory cosmetic properties when dry, including, in particular, elasticity, body, sheen and manageability. In contrast to the prior art, wherein cationic polymers were blended primarily with amphoteric surfactants, the hair shampoo-conditioner composition of the present invention includes a particular polymeric conditioning compound to condition the hair and an anionic surfactant to cleanse the hair. In addition, the stability and incompatibility problems normally encountered when a cationic compound and anionic surfactant are present in the same composition have been overcome.
Previous attempts to provide a combination shampoo-conditioner composition include the disclosure of Goff in U.S. Pat. No. 2,950,255, wherein relatively small, equimolar amounts of an anionic surfactant and a monomeric quaternary ammonium surfactant are included in a hair shampoo based primarily on amphoteric and nonionic surfactants. Amphoteric and nonionic surfactants are mild detergents and are compatible with cationic surfactants, but are not as effective in generating foam or in cleansing the hair as anionic surfactants. Similarly, Anguillo et al., in U.S. Pat. No. 3,816,616, discloses the use of a guar gum-based cationic polymer in an anionic surfactant-based shampoo to provide a combination hair shampoo-conditioner composition. The compositions disclosed by Anguillo et al. were found to clean efficiently but are inefficient in imparting conditioning properties to the hair.
Gerstein, in U.S. Pat. No. 3,990,991, discloses a hair shampoo-conditioner composition comprising major amounts of an amphoteric surfactant and an ethoxylated or propoxylated cryptoanionic surfactant, with a minor amount of a cationic surfactant or cationic polymer. U.S. Pat. No. 4,061,602 to Oberstar et al. discloses a conditioning shampoo composition, comprising an amphoteric surfactant, an anionic surfactant and a cationic derivative of a naturally-occurring polymer, that cleans and imparts conditioning properties to the hair. Koehler et al. in U.S. Pat. No. 4,273,760 discloses a hair conditioning shampoo including a cationic polymer, an anionic surfactant and a nonionic surfactant that conditions and cleanses the hair
Barker in U.S. Pat. No. 4,247,538 discloses a conditioning shampoo comprising an amphoteric surfactant base, a cationic surfactant and an anionic macrocolloid polymer. Cseh, in U.S. Pat. No. 4,676,978, discloses a conditioning shampoo that includes a polycationic guar derivative, a hardenable cationic polycondensation product, a nonionic surfactant, and a film-forming polymer in an anionic surfactant-based shampoo. Scandel, in U.S. Pat. No. 4,832,872, teaches a hair shampoo-conditioner including an anionic surfactant, a conditioning amine oxide, and a conditioning cationic quaternary polymer.
Homma et al., in U.S. Pat. No. 4,381,259, disclose a hair shampoo-conditioner composition comprising a surfactant effective for washing hair, an anionic phosphoric acid ester surfactant and a cationic polymer. Specifically, Homma et al. disclose, at column 4, lines 37-39, that a suitable cationic polymer is a copolymer of adipic acid and dimethylaminohydroxypropylene diethylenetriamine. This polymer differs from the polymer utilized in the present invention in that a nitrogen atom of the diethylenetriamine is substituted with a propylene moiety including a hydroxy substituent and a dimethylamino substituent. The copolymer utilized in the present invention does not include a substituent on a nitrogen atom of the polyamine. Further, the composition and method of the present invention do not require an anionic phosphate ester surfactant to generate a sufficient foam volume, to cleanse the hair or to impart conditioning properties to the hair.
The following additional patents and publications also are directed to hair shampoo-conditioner compositions and compounds used in hair shampoo-conditioner compositions: A. Hunting, "The Function of Polymers in Shampoos and Conditioners", Cosmet. Toiletries, 99(6), 57-60, 1984; Coney, U.S. Pat. No. 3,793,210; Olson, Jr. et al., U.S. Pat. No. 3,697,452; Hewitt, U.S. Pat. Nos. 3,755,559, 3,849,348 and 3,642,577; Tarasov et al., U.S. Pat. No. 3,996,146; Birkofer, U.S. Pat. No. 3,926,840; Barker U.S. Pat. No. 3,668,136. The prior art teaching that an amphoteric detergent is necessary in a shampoo-conditioner composition is exemplified by the following patents directed to conditioning shampoos U.S. Pat. Nos. 3,313,734; 3,962,418; 2,999,069; 3,055,836; 3,996,146; 4,009,256 and 3,400,198. These patents, and others, teach the necessity of including an amphoteric or polar nonionic component in the composition to achieve compatibility between the cationic conditioning compound and the remaining components of the shampoo formulation.
Forestier et al., in U.S. Pat. No. 4,866,159, disclose the use of a polyaminoamide in a skin care or a hair care product to filter ultraviolet radiation, and therefore to protect the skin or hair from harmful solar radiation. Forestier et al. specifically disclose a crosslinked polyaminoamide including a condensation product of a dicarboxylic acid and a polyamine partially substituted with an ultraviolet radiation absorbing moiety. The substituted condensation product is incorporated into a skin care or a hair care composition in a sufficient amount to protect the treated skin or hair from ultraviolet radiation. The Forestier et al. disclosure does not teach or suggest the use of a substantially uncrosslinked, unsubstituted copolymer of a dicarboxylic acid and polyamine as a hair-conditioning compound that does not adversely affect the ability of an anionic surfactant-based composition to generate a stable and copious foam volume.
As will be shown in the following detailed description of the invention, these references fail, singly or in combination, to anticipate or suggest the composition and method of the present invention, wherein a polymeric conditioning compound is combined with an anionic cleansing surfactant, at a pH of from about 2.5 to less than 7, to provide a sufficiently stable hair shampoo-conditioner composition that effectively, and simultaneously, generates a copious and stable foam volume, cleanses the hair and imparts improved conditioning properties to the hair. Surprisingly, the composition of the present invention is sufficiently stable to resist phase separation even though both an anionic surfactant and a cationic component are present in the composition. Furthermore, the composition demonstrates a superior ability to generate a thick, stable lather and to deposit the conditioning agent on the hair without exhibiting an excessive build-up of the polymeric conditioning compound on the hair shaft after repeated shampooings.
Therefore, and in accordance with the present invention, the hair is cleansed and, simultaneously, excellent hair conditioning properties are imparted to the hair by a method of contacting the hair with a composition comprising an anionic cleansing surfactant and a particular polymeric conditioning compound, and having a pH of from about 2.5 to less than 7. Consequently, the method of the present invention provides a copious and stable foam, and both cleanses the hair and conditions the hair to provide more manageable and esthetically-pleasing hair in a single application of the shampoo-conditioner composition to the hair.